<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        .dv1 {
            border: 1px solid red;
            width: 200px;
            height: 200px;
            display: flex;
        }

        .dv1>div:nth-child(1) {
            border: 1px solid blue;
            display: flex;
            flex-flow: column;
            flex: 1;
        }

        .dv1>div:nth-child(1)>div:nth-child(1) {
            background: red;
            flex: 1;
        }

        .dv1>div:nth-child(1)>div:nth-child(2) {
            background: yellow;
            flex: 1;
        }

        .dv1>div:nth-child(2) {
            background: blue;
            flex: 1;
        }


        /* 第二个div */
        .dv2 {
            /* 主div */
            display: flex;
            flex-flow: column;
            text-align: center;
        }

        .dv2>div:nth-child(1) {
            /* 顶部 */
            background: rebeccapurple;
            flex: 1;
        }

        .dv2>div:nth-child(2) {
            /* 中间的可滚动的div */

            background: red;
            flex: 5;
            overflow: hidden;
            overflow-y: scroll;
        }

        .dv2>div:nth-child(2)>div:nth-child(1) {
            /* 这是两个样式加不加都行 */
            background: white;
        }

        .dv2>div:nth-child(2)>div:last-child {
            /* 这是两个样式加不加都行 */

            background: white;
        }

        .dv2>div:nth-child(3) {
            /* 底部的div */
            background: blue;
            flex: 1;
        }

        ::-webkit-scrollbar {
            display: none;
        }

        /* 第二个div 结束*/


        .dv3 {
            display: flex;
            flex-flow: column;
            min-width: 10px;
        }

        .dv3>div:nth-child(1) {

            border: 1px solid red;
        }

        .dv3>div:nth-child(2) {
            flex: 9;
            border: 1px solid rgb(0, 17, 255);
        }

        .dv3>div:nth-child(3) {

            border: 1px solid rgb(15, 236, 181);
        }
    </style>
</head>

<body>



    <div class="dv1">
        <div>
            <div>1</div>
            <div>2</div>
        </div>
        <div>3</div>
    </div>


    <div class="dv2" style="border: 1px solid red; width: 300px;height: 500px;">
        <div>1</div>
        <div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
            <div>123</div>
        </div>
        <div>3</div>
    </div>

    <div class="dv3" style="width: 100vw; height: 100vh; border: 1px solid red;  padding: 1% ;
    box-sizing: border-box;">
        <div style="display:flex; ">
            <div style="width: 100px; height: 100px; background: rebeccapurple ;">123</div>
            <div style="flex: 1;background: red;">456</div>
        </div>
        <div style="display:flex;">
            <div style="flex: 2;background: rgb(250, 234, 15);">a1</div>
            <div style="flex: 3; background: slategrey;">a2</div>
            <div style="flex: 1; background: salmon;">a3</div>
        </div>
        <div style=" height: 100px !important; background: rgb(15, 236, 181);">1</div>

    </div>
</body>

</html>